c# - 对象必须实现 IConvertible

Question

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.InvalidCastException: Object must implement IConvertible.

来源错误:

Line 20:         public ActionResult Index()
Line 21:         {
Line 22:             var feeds = (from f in _db.AlertRules.Include("AlertRuleOutages")
Line 23:                          select f).ToList();
Line 24: 

堆栈跟踪:

[InvalidCastException: Object must implement IConvertible.]
   System.Convert.ChangeType(Object value, Type conversionType, IFormatProvider provider) +9508841
   MySql.Data.Entity.EFMySqlDataReader.ChangeType(Object sourceValue, Type targetType) +376
   MySql.Data.Entity.EFMySqlDataReader.GetValue(Int32 ordinal) +129
   System.Data.Common.Internal.Materialization.ErrorHandlingValueReader`1.GetValue(DbDataReader reader, Int32 ordinal) +215
   lambda_method(Closure , Shaper ) +468
   System.Data.Common.Internal.Materialization.Shaper.HandleEntityAppendOnly(Func`2 constructEntityDelegate, EntityKey entityKey, EntitySet entitySet) +218
   lambda_method(Closure , Shaper ) +218
   System.Data.Common.Internal.Materialization.Coordinator`1.ReadNextElement(Shaper shaper) +170
   System.Data.Common.Internal.Materialization.RowNestedResultEnumerator.MoveNext() +235
   System.Data.Common.Internal.Materialization.ObjectQueryNestedEnumerator.TryReadToNextElement() +16
   System.Data.Common.Internal.Materialization.ObjectQueryNestedEnumerator.MoveNext() +57
   System.Collections.Generic.List`1..ctor(IEnumerable`1 collection) +327
   System.Linq.Enumerable.ToList(IEnumerable`1 source) +58

数据库 DDL:

CREATE TABLE alertruleoutage
(
Id        INT NOT NULL auto_increment,
RuleId    INT NOT NULL,
StartTime TIME NULL DEFAULT 00:00:00,
EndTime   TIME NULL DEFAULT 23:59:59,
WeekDays  TINYINT NULL,
Count     INT NULL,
TimeFrame TIME NULL DEFAULT 01:00:00,
PRIMARY KEY (Id),
KEY RuleId (RuleId),
CONSTRAINT RuleId FOREIGN KEY (RuleId) REFERENCES alertrule (Id)
);



CREATE TABLE alertrule
    (
    Id             INT NOT NULL auto_increment,
    FeedId         INT NOT NULL,
    TemplateId     INT NOT NULL,
    Enable         BIT (1) NULL DEFAULT b'1',
    `Rule`         VARCHAR (250) NULL,
    UpdateDateTime TIMESTAMP NULL DEFAULT CURRENT_TIMESTAMP on update CURRENT_TIMESTAMP,
    PRIMARY KEY (Id),
    KEY AlertFeedId (FeedId),
    KEY AlertTemplateId (TemplateId),
    CONSTRAINT FK_AlertFeedId FOREIGN KEY (FeedId) REFERENCES feed (Id),
    CONSTRAINT FK_AlertTemplateId FOREIGN KEY (TemplateId) REFERENCES alertruletemplate (Id)
    );

POCO 模型:

 [Table("AlertRuleOutage")]
public class AlertRuleOutage
{
    [Key]
    public int Id { get; set; }

    public int RuleId { get; set; }

    public DateTime? StartTime { get; set; }

    public DateTime? EndTime { get; set; }

    //public Week WeekDays { get; set; }

    public int? Count { get; set; }

    public DateTime? TimeFrame { get; set; }

    public virtual AlertRule Rule { get; set; }
}

    [Table("AlertRule")]
public class AlertRule
{
    [Key]
    public int Id { get; set; }

    public int FeedId { get; set; }

    public int TemplateId { get; set; }

    public bool? Enable { get; set; }

    public string Rule { get; set; }

    public DateTime? UpdateDateTime { get; set; }

    public virtual Feed Feed { get; set; }

    public virtual AlertRuleTemplate Template { get; set; }

    public virtual List<AlertRuleOutage> AlertRuleOutages { get; set; }
}

数据库上下文:

    public DbSet<AlertRule> AlertRules { get; set; }

    public DbSet<AlertRuleOutage> AlertRuleOutages { get; set; }

Answer 1

AlertRuleOutage 中的数据类型错误

mysql Time 应映射到 .NET TimeSpan:

public TimeSpan? StartTime { get; set; }

另见: http://www.devart.com/dotconnect/mysql/docs/DataTypeMapping.html